But this is the first time Athens has put an official number -- roughly $300 billion -- on World War II reparations.

The German government has -- again -- dismissed the claims, saying the matter has long been closed. "They won't get their debts paid by conjuring up German obligations from World War II," German finance minister Wolfgang Schaeuble told German media last month.

Germany paid Greece 115 million marks in 1960, as required by reparation agreements. On top of that, it also paid compensation directly to individual victims of the Nazi regime in Greece -- forced laborers, for example.

Berlin says the issue of reparations was settled once and for all by the international treaties that cleared the way for German reunification in 1990.

"The 1960 agreement provided reparations only for the victims of Nazism in Greece, not for the damage inflicted on the country itself," Prime Minister Alexis Tspiras said in March, when he launched a commission to establish the size of the claim and suggest ways of resolving the dispute.

Athens also says those reparations did not cover an interest-free loan that occupied Greece was forced to make to the Nazis in 1942. The loan was never repaid.

The estimate of damages comes as Germans are losing patience with Greece over its attempts to renegotiate the terms of its massive bailout.

The Greek government has not made any formal request for reparations but opinion polls show a claim would have widespread popular support in Greece, which is struggling to avoid another financial collapse.

But Tspiras went as far as suggesting Greece could start confiscating German assets if Berlin refuses to pay.